1. Technical Field
The present invention relates to a projector that projects an image on a projection surface and a method of controlling a projector.
2. Related Art
In a case where an image is projected onto a projection surface such as a screen by a projector, it is known that an image formed on the projection surface is distorted in accordance with a projection angle of the projector. A general projector has a trapezoidal distortion correction function for transforming a projected image into a correct shape on the projection surface. In addition, for example, there is a projector that automatically performs trapezoidal distortion correction by projecting a predetermined pattern on a projection surface, capturing an image of the projection surface onto which the pattern is projected, and detecting the deformation of the pattern in the captured image (for example, see JP-A-2010-128102).
However, in a case where the trapezoidal distortion becomes prominent again due to a movement of the projector or a change in the direction of the projector after the trapezoidal distortion correction, the trapezoidal distortion correction is performed again. In such a case, it may be difficult to maintain the accuracy and the speed of correction that is equivalent to those of a case where the trapezoidal distortion correction is performed for the first time. In other words, in the trapezoidal distortion correction performed first time, commonly, trapezoidal distortion occurs in an image projected in a rectangular shape, and accordingly, the projected image is transformed such that the trapezoidal distortion is offset with reference to a rectangular state. In order to realize the transformation, in a display unit included in the projector, an image is displayed in a scale smaller than a displayable area. Accordingly, in the trapezoidal distortion correction performed for the second time and after that, trapezoidal distortion is detected based on an image displayed in a scale smaller than that in the trapezoidal distortion correction performed for the first time. Therefore, the accuracy of a process for calculating the amount of correction and the correction direction in the trapezoidal distortion correction or the speed of the process may not be equivalent to those of the trapezoidal distortion correction performed for the first time.